This invention relates to an uneven ground vehicle to be used in the field of agriculture, forestry or mining, and more particularly to an uneven ground vehicle suitable for its use on a snow-covered road and a field of civil engeering works.
In the field of agriculture, forestry or mining, an uneven ground vehicle having endless belts or crawlers has been used in addition to a normal vehicle because the endless belts or the crawlers have a big area of ground contact and can produce a big tractive force.
However, in such an uneven ground vehicle having caterpillars or crawlers, a complete ground contact cannot be necessarily ensured when the vehicle runs on an uneven or a rough ground thereby to decrease its tractive force. For example, when the vehicle moves from an upgrade surface to a downgrade surface, first, the front part of the body of the vehicle is floated from the ground surface shortly before the vehicle passes by a top surface between the upgrade and downgrade surfaces and the rear part of the body thereof is then jumped up from the ground surface shortly after the vehicle passes by the top surface. Further, when the vehicle comes to a raised ground, the body of the vehicle is much inclined. In the case of floating and jumping of the body of the vehicle, area of ground contact as well as tractive force is decreased thereby to be uncomfortable to drive. In contrast, when the vehicle moves from a downgrade ground surface to an upgrade ground surface, the intermediate part of the body is floated from the ground surface in a state wherein the front and rear parts of the body contact the ground surface. Also at this time, area of ground contact becomes small and the body of the vehicle is swung much. Especially, in case that a metal endless belt or crawler is used, there are defects such as insufficient speed, generation of noise and damage of a road surface.
Moreover, a normal vehicle having a plurality of tires or wheels cannot produce a sufficient tractive force and, therefore, the use of the vehicle on an uneven or a rough ground is restricted. In addition, a big inclination of the body thereof upon passing over a raised ground is a problem.